Database Design Chapter 3

Terminology Why this terminology is important Value-Related Terms Structure-Related Terms Relationship-Related Terms Integrity-Related Terms

Why This Terminology is Important It is used to express and define the special ideas and concepts of the RDM it is used to express and define the database design process itself it is used anywhere a relational database or RDMS is discussed

Value-related Terms Data Information Null values that are stored in the database Information data that has been processed in a way that makes it meaningful Null value is missing or unknown zero and blanks are not null

Structure-related Terms Table (relation) contains fields and records order unimportant represents objects clients, students, classes represents events Patient visit validation table holds data specifically for data integrity

"Field (attribute)" Field (attribute) Record (tuple) smallest structure in relational database characteristic of the subject of the table multipart, multivalued, calculated field types Record (tuple) unique instance of the subject of the table composed of fields

"View" View Keys virtual table composed of fields from 1 or more tables or validation tables saved queries Keys primary key - uniquely identifies a record within the table foreign key - field used to establish relationship

"Index" Index used to improve data processing has nothing to do with logical database structure keys are logical structures to identify records indexes are physical structures used to optimize data processing

Relationship-related Terms Relationships connection between a pair of tables connected by primary and foreign keys connected by linking table increase data integrity reduce redundancy used as means to define views

Types of relationships (cardinality) one-to-one single record in the first table related to ONLY one record in the second table one-to-many single record in the first table related to one or many records in the second table single record in second table related to only one record in the first table Many-to-many single record in first table can be related to many in the second table single record in second table can be related to many in the first table